**Calculating the number of carbon atoms in benzene**

To determine the number of carbon atoms in 7.8 grams of benzene, we need to follow a step-by-step process.

**Step 1: Determine the molar mass of benzene**
The molar mass of benzene (C6H6) is calculated by summing up the atomic masses of its constituent elements. The atomic mass of carbon (C) is 12.01 g/mol, and there are 6 carbon atoms in benzene. The atomic mass of hydrogen (H) is 1.01 g/mol, and there are 6 hydrogen atoms in benzene. Therefore, the molar mass of benzene is:
(6 * 12.01 g/mol) + (6 * 1.01 g/mol) = 78.11 g/mol

**Step 2: Convert grams to moles**
Using the molar mass of benzene, we can convert the given mass of benzene (7.8 g) to moles. The conversion is done using the formula:
moles = mass / molar mass
moles = 7.8 g / 78.11 g/mol = 0.1 mol

**Step 3: Determine the number of moles of carbon**
In benzene, there are 6 carbon atoms per molecule. Therefore, the number of moles of carbon is equal to the number of moles of benzene multiplied by the ratio of carbon atoms to benzene molecules. This can be calculated as:
moles of carbon = moles of benzene * (6 carbon atoms / 1 benzene molecule)
moles of carbon = 0.1 mol * 6 = 0.6 mol

**Step 4: Convert moles to atoms**
To determine the number of carbon atoms, we need to convert moles of carbon to the number of atoms. Avogadro's number (6.022 x 10^23 atoms/mol) is used for this conversion. The formula is:
number of atoms = moles of carbon * Avogadro's number
number of atoms = 0.6 mol * 6.022 x 10^23 atoms/mol ≈ 3.613 x 10^23 atoms

Therefore, there are approximately 3.613 x 10^23 atoms of carbon present in 7.8 grams of benzene.

7.8/78×6×Na(avogadro.no)